Coupling of a treatment system to tissue is important for clinical efficiency of the desired treatment. In addition, using a treatment system that is not coupled to tissue may cause safety concerns. Further, if a treatment system is not properly coupled to the tissue may cause stability and performance issues. Various contact sensors have been used to determine if a treatment system is coupled to targeted tissue. However, these contact sensors typically use mechanical methods to determine if a treatment system is coupled to the tissue. Accordingly, new approaches for determining whether a treatment system is coupled to targeted tissue are needed.